I would go with wood. All you really need to do for an easy grow box is get some plywood and a staple gun. Then cut out your sides top bottom etc and staple together. I am actually building one right now in woodshop
if i was you i would just get a tent. i built mine out of wood and i could of bought a tent for the same price. i am kicking myself for not getting the tent.
i used 1x1 for a frame, wraped it in vapor barrier and lined the inside with white shower curtains on top of black garbage bags.. most of the materials i had round the house... the most expensive thing was the red contracters tape.. no smell gets in or out nor does light